The present invention relates to a defect examination apparatus. More particularly, the present invention relates to a defect examination apparatus for detecting defect locations of a plurality of to-be-inspected objects which are vertically and horizontally placed according to a prescribed rule.
Widely known is a defect examination apparatus for detecting a defect of a solder bump (hereafter simply referred to as a bump) as a to-be-inspected object which is formed on, say, a printed circuit board.
Though not prior art (accordingly not disclosed), the applicant proposed, in Jpn. Pat. Appln. No. 10-339335, an example of such a defect examination apparatus for comprehensively judging defects according to an inspection result from a plurality of image measuring means. This defect examination apparatus stores correspondence between information about bumps inspected by a plurality of image measuring means and ID information indicating each bump location.
The defect examination apparatus finds a matrix number as ID information for indicating each bump location as follows. To find a row number, for example, any bump is used as a reference for searching a horizontally adjacent bump. The found bump is used as a new reference for further searching an adjacent bump. This search is repeated in both directions until no bump is found. When final bumps are found at both ends, these bumps are connected with a line which is used as a reference line. A row number can be found according to a distance from this reference line to each bump and a predefined pitch size.
Jpn. Pat. Appln. KOKAI Publication No. 10-062121 discloses the following method. Namely, an obtained BGA (ball grid array) image is used for finding a slant of a BGA ball array""s external edge. An intersection point is found for external edges of vertical and horizontal BGA ball arrays. The found slant and the intersection point are used for accurately measuring BGA ball locations.
Further, Jpn. Pat. Appln. KOKAI Publication No. 10-288505 discloses the method for locating a work. According to this method, a plurality of members having a specified size is arranged by a specified rule on a face of a work under examination. Before a full-scale inspection, an approximate location of this work can be specified accurately and fast.
However, the defect examination apparatus described in Jpn. Pat. Appln. No. 10-339335 causes the following problems. As shown in FIG. 16, there may be dust 2002 at an end along a search direction. If the dust 2002 is found as a bump 2000, a reference line 2001 to be found is slanted against an array of bumps 2000, preventing a row number from being found correctly. Searching adjacent bumps causes inconvenience of having to specify a pitch size as a design value or a search range sufficiently including a pitch size as a design value. It is very time-consuming to search as many as several thousand bumps and check these bumps one by one if each bump is adjacent to a reference bump. The use of more than one pitch size provides an incorrect row or column number.
In Jpn. Pat. Appln. KOKAI Publication Nos. 10-062121 and 10-288505, complicated operations are needed beforehand for detecting an array and a slant of bumps. Namely, part of a region under examination must be limited for calculating an array and a slant of bumps.
For example, the explanation with reference to FIGS. 3, 4, and 13 in Jpn. Pat. Appln. KOKAI Publication No. 10-062121 contains description about specification of regions b1, b2, and the like including a column of bumps. It is considered that operations for this portion need to be updated each time a sample is changed. Though it is possible to automate these processes, they are still complicated and time-consuming. Also in Jpn. Pat. Appln. KOKAI Publication No. 10-288505, it is necessary to appropriately specify a region including a column or row of bumps beforehand.
In Jpn. Pat. Appln. KOKAI Publication Nos. 10-062121 and 10-288505, there are provided two inspection frames for finding an approximate slant. The method is used to find locations which greatly vary the total brightness in these inspection frames. However, this method may yield an incorrect slant if there is dust.
In Jpn. Pat. Appln. KOKAI Publication Nos. 10-062121 and 10-288505, the method is used to rotate an inspection frame and assume an angle to be a slant when the total brightness in the inspection frame becomes maximum. However, this method may yield an incorrect slant depending on where to specify a rotation center in the inspection frame.
Jpn. Pat. Appln. KOKAI Publication Nos. 10-062121 and 10-288505 disclose only the method for finding a slant in the row direction. A slant in the column direction is assumed to be orthogonal to the slant in the row direction. No specific method is disclosed. There is provided no method for finding a matrix number.
Jpn. Pat. Appln. KOKAI Publication No. 10-62121 is inapplicable to irregularly arranged bumps which do not follow a prescribed rule. Jpn. Pat. Appln. KOKAI Publication No. 10-288505 discloses a method for processing an array having an irregular pitch. However, there is a problem of previously providing information about the number of bumps and a distance between bumps in a bump column.
It is therefore an object of the present invention to provide a defect examination apparatus which can number a plurality of to-be-inspected objects accurately and fast.
It is another object of the present invention to provide a defect examination apparatus which can implement numbering without necessitating previous information even if there exist irregularly arranged bumps not following a prescribed rule.
It is yet another object of the present invention to provide a defect examination apparatus which can achieve correct correspondence among different sensors or works even if same numbers are not assigned.
For achieving the above-mentioned objects, the first aspect of the present invention is a defect examination apparatus for detecting defect locations of a plurality of to-be-inspected objects vertically and horizontally arranged according to a prescribed rule, comprising:
blob analysis means for finding location coordinates of the plurality of to-be-inspected objects;
rotation angle calculation means for finding a rotation angle for a horizontal series of the plurality of to-be-inspected objects against a horizontal line and a rotation angle for a vertical series of the plurality of to-be-inspected objects against a vertical line based on a location coordinate found by the blob analysis means;
pitch size calculation means for finding vertical and horizontal pitch sizes of the plurality of to-be-inspected. objects; and
matrix number analysis means for finding a matrix number for each to-be-inspected object based on a rotation angle found by the rotation angle calculation means and a pitch size found by the pitch size calculation means.
The second aspect of the present invention is a defect examination apparatus for detecting defect locations of a plurality of to-be-inspected objects vertically and horizontally arranged according to a prescribed rule, comprising:
blob analysis means for finding location coordinates of the plurality of to-be-inspected objects;
rotation angle calculation means for finding a rotation angle for a horizontal series of the plurality of to-be-inspected objects against a horizontal line and a rotation angle for a vertical series of the plurality of to-be-inspected objects against a vertical line based on a location coordinate found by the blob analysis means; and
matrix number analysis means for finding matrix numbers for the plurality of to-be-inspected objects based on a rotation angle found by the rotation angle calculation means.
The third aspect of the present invention is a defect examination apparatus for detecting defect locations of a plurality of to-be-inspected objects vertically and horizontally arranged according to a prescribed rule, comprising:
blob analysis means for finding location coordinates of the plurality of to-be-inspected objects;
rotation angle calculation means for finding a rotation angle for a horizontal series of the plurality of to-be-inspected objects against a horizontal line and a rotation angle for a vertical series of the plurality of to-be-inspected objects against a vertical line based on a location coordinate found by the blob analysis means;
pitch size calculation means for finding vertical and horizontal pitch sizes of the plurality of to-be-inspected objects; and
cell creation means for virtually finding lattice lines based on a rotation angle found by the rotation angle calculation means and a pitch size found by the pitch size calculation means and for virtually creating a cell of a size based on the pitch size at each intersection point of the lattice lines; and
number analysis means for assigning matrix numbers to a plurality of cells created by the cell creation means and for numbering the plurality of to-be-inspected objects by using the cells assigned with corresponding matrix numbers.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.